The control of animal parasites is one of the oldest and most important problems of the animal husbandry industry. Many types of parasites afflict virtually all species of animals. Most animals are afflicted by free-flying parasites such as flies, crawling ectoparasites such as lice and mites, burrowing parasites such as bots and grubs, and by microscopic endoparasites such as coccidia, as well as by larger endoparasites such as worms. Thus, the control of parasites even in a single host species is a complex and many-sided problem.
The insect and acarina parasites which consume living tissues of a host animal are particularly harmful. The group includes parasites of all the economic animals, including ruminant and monogastric mammals and poultry, and of companion animals such as dogs as well.
Many methods of control of such parasites have been tried. The screwworm has been practically eradicated in Florida by the release of great numbers of sterile male blowflies. The method obviously is applicable only to an easily isolated area. The free-flying insects are usually controlled by routine methods such as air-dispersed and contact insecticides and fly traps. The skin-inhabiting, crawling parasites are usually controlled by dipping, drenching, or spraying the animals with appropriate parasiticides.
Some progress has been made in the systemic control of some parasites, particularly those which burrow in or migrate through the host animal. Systemic control of animal parasites is accomplished by absorbing a parasiticide in the bloodstream or other tissues of the host animal. Parasites which eat or come into contact with the parasiticide-containing tissue are killed, either by ingestion or contact. A few phosphate, phophoramidate, and phosphorothioate insecticides and acaricides have been found to be sufficiently nontoxic to be used systemically in animals.
The field of o-phenylenediamine chemistry has produced many patents. For example, Rumanowski, U.S. Pat. No. 3,557,211, discloses N,N'-bis(acetyl)-o-phenylenediamines which are useful for the control of plants, insects and fungi.